New old experience.

Weee... There is no hidden room at my house. Just a thicker wall and my little mistakes in measuring. :) But I would say luckily because it would mean an extra wall to be ripped out.

Another thing is that today I bought 36 4-watt solar wafers and some ribbon to spin it together.  I would try to build a 145 W solar panel using my own hands. It's been over 20 years since with a help of my neighbour I had assembled my first color TV-set but I hope I can still deal with soldering tool.  I am going also to make some tests on them to determine how to improve their yield in poor insolation condition.

If you have tried different types of batteries please let me know what are the best for everyday usage. I'm sure that gel based used in computer APCs are pretty bad according to my experience.

Sewage treatment unit.

First thing I will acquire for my house is sewage treatment unit. After long consideration I decided for biologically-ecological model. Although it uses some electricity (80 W pump working 15 min then 15 min break - so approx. 40W of permanent consumption) it gives you quite good quality water in the end. So it do not need to be drained in the ground. I plan to collect it in the small pond and use it for watering garden. Even without "oxygen stage" induced by air pump it will still work such as ordinary ecological unit based only on anaerobic process. Maybe the water quality in the end pipe will be not so good at that time but we are talking only about period of "disaster" and at that time my garden will be watered from other sources if needed.

The only maintenance cost is once a year take a mud from the first reservoir. Cost of such unit (2,5 m3 - up to 5 users) should return within 4-5 years. What is most important form preppers point of view it will make me totally independent in terms of sewage. 

Of course I plan to have photovoltaic installation to which I plan to connect my sewage treatment unit to keep it operating with aerobic process even if the electricity fail.